PERHITUNGAN CADANGAN BATU GRANIT DENGAN METODE PENAMPANG MELINTANG (CROSS SECTION) DI PT. GILGAL BATU ALAM LESTARI KECAMATAN SUNGAI KUNYIT KABUPATEN MEMPAWAH PROVINSI KALIMANTAN BARAT

Abstract

PT Gilgal Batu Alam Lestari is a mining company that uses granite as its main mineral. The mining system used by the company is an open pit mine (quarry) with unloading, loading and hauling mining channels. Reserves are an important element that must be known because they involve products from a mining activity that will be sold and are one of the determining factors for profit and loss. The method used in this study is the cross-sectional method. The results of topographic mapping in the quarry area of PT Gilgal Batu Alam Lestari using a Total Station have changed hue in the quarry area with the highest elevation topography of 75 meters and the lowest of 30 meters. The volume and tonnage of granite that has been mined is calculated using the cross section method and the result is 163,906.93 m³ or 819,534.65 tons. The percentage of mined reserves obtained was 14.03% of the initial total reserves of 342,673.98 m³ or 1713369.93 tons. If PT Gilgal Batu Alam Lestari can continue to produce 160,000 m³/year of granite, then the remaining life of the granite mine of PT Gilgal Batu Alam Lestari is 7 years and 1 month.